Would You Consider Sailing, But Without Sails?

I'll probably never get round to building this, but hope I'm planting seeds.

I'd intended on using a diesel generator as back up, you're right there.

The Vertical Axis Wind Turbines, I see problems with, I'll post a link to the problems. http://www.motherearthnews.com/renewable-energy/vertical-axis-wind-turbines-zmaz08fmzmcc.aspx?PageId=1

The catamaran hull, I like the idea, but, and this but may be wrong, I only see them as more stable to a point, it seems that once they start to capsize, you're not going to stop them. This will be even worse with the weight on top, and may be impossible to right.

Thank you for not being discouraging.

 

Thanks for the link, unfortunately it wont open for me, ill try again later. Im no expert on this and always willing to learn. What I like about the vertical format is that I believe it could be easily stayed, especially on a catamaran platform, which would allow for a lighter build and a lower center of gravity reducing the likelihood of capsize. I also think it would be safer than a large windmill above your head but this is just a feeling. Most important though is that nothing is more secure than a cat for disabled folk to move around on if wheelchair bound. Im sure the windmill must be more efficient than the vertical type or we wouldn't have all the windfarms built in that format but I think you need to consider all factors. The windfarm genorators put the generator up at the top directly driven by the blades, presumably to prevent the losses from 90 degree bevel gears, this puts a lot of weight up high, not a big deal out in a field but it is on a boat. With vertical the whole thing could rotate around a stayed central mast driving a generator at deck level or below, just 2 or 3 bearings, low cg and if you stay it you can get the weight way down and its omnidirectional. I don't see how you could stay a windmill as it needs to be able to swino expert on thisg around to face the wind so if it needs to be free standing the weight goes waaay up. Please understand im no expert on this subject, i know a little bit about a lot of things, sometimes probably just enough to be dangerous.

Steve.

 

You do need to take a look at that link, and follow on through the next pages, it's a real eye opener.

I'd thought of dropping the generator part down to almost deck level, but using drive belts from the hub, and having the mast rotate from just below it. Far more efficient than gears, and maybe make the catamaran a possibility.

No problem knowing just enough to be dangerous, it helps creativity.

 

Herreshoff played with wind powered propeller turning a water propeller, a very basic design so they probably also thought to run an under water propeller of using wind to turn a generator and motor.

 

There have been many advances in rotor, generator, and motor design since Herreshoff's era. Batteries have come a long way too.

I hope I'm referring to the correct Herreshoff though.

 

If this direction does have merit, a scaled down version would likely demonstrate it's virtues at lower cost and risk. A wind powered trolling rig would be such an application. If you can build an all in one wind powered trolling motor you would have a viable product and potentially a revenue stream to finance your proposal.

That article thrashing vertical rotors strikes me as too much opinion with no data. I believe verticals are less efficient, but I don't believe they are intrinsically heavier and more complex. The big problem with rotors on boats is the motion of waves causing great variation in wind speed and direction, and I think vertical rotors are more forgiving in that environment.

 

Ok ive read that article, it seems many disagree with the author,i can see the point though regarding the orientation but he is talking about a 2 bladed rotor,the large one I saw in New Zealand 40 years ago had 3 i believe which would clearly be better. Also as a boatbuilder I know I could build it light and as I mentioned before, the CG would be lower with the generator located below decks as well as being easy to keep the electric components protected from moisture.

Steve.

 

OD I too read the article, and frankly they get a bunch of stuff right but a bunch of stuff they make up. For example they conflate the dynamic load design requirements of the turbine blades with "wear and tear" and the two are different. on a Darreius vertical turbine, you have no need for a mechanism to feather into the wind. That's a gearing mechanism that simply is extra on the straight bladed turbine. Or else you use a "tail vane" (as the old plains water wells did) but that adds weight aloft and parasitic drag in the wrong direction. and you still need an alternative swiveling bearing surface.

The horizontal turbines also have the issue that their bearing shaft is assymetrically loaded (the front bearing receives a vertical down force and the leeward bearing gets a coupled upward force) so you have to build extra strength into the upper part of the mast to deal for this tortional load.

Now on land, weight aloft is primarily an initial CAPEx cost. and 5%-10% more efficiency more than makes up for that, but on a sea going platform weight aloft has dramatic adverse stability effects and the Darreius is going

Now as to stability of the platform - one of the serious problems with a windmill in a seaway is the precessional forces involved. again here the fan style windmill is worse off. Basically in a lot of the motions that the boat is going to go through, you end up with the windmill INCREASING the amplitude of any wave induced motion, whereas in the Darreius style model mostly your gyroscopic precession will be operating in the yaw plane.

Lastly a boat is moving whereas a land based mill is not. This is important. Because if you think about at a Darreius style mill can be thought of as a self-powered Flettner rotor (think lots of blades close together). And once you start moving that will generate an additional lift force

 

I really don't think a scaled down version would work, I'd like it to, but don't think it could be done.

The problem that I see with the VAWT, is a simple one, (maybe I'm over simplifying this), but you have at least one blade being pushed by the wind, and another always being driven by that blade, into the wind, you can only get power from the imbalance between the two.

 

It's the power output of the VAWT, that I see as the problem, I don't have a formula for calculating it. From comparing rated outputs of a few though, it seems that you don't get much of a power increase as the wind speed rises. This, you do get from a HAWT.

Having the generator below decks would be an improvement over my idea though. I had thought of it for my idea, but the power losses through gears would have been too great for it to work.

You being a boatbuilder is really helpful here, and that you could build it. After starting this thread though, I'm not really sure there is, or would be a market for such a boat.

 

All good points you've made there, very helpful, and a lot more for me to consider.

Thank you.

 

Why would you think large could work if small doesn't?

Vertical is not as 'efficient' as Horizontal windmill, on land, theoretically. So applied to a pitching boat boat that means precisely... nothing. I read your statement as saying you don't understand VAWT and you don't like them. I am telling you you should look into VAWT because it is far more robust and simple. You stand no chance of getting the the (land based) efficiency you are crediting the horizontal mill with and you can't cope with it's complexity.

The low VAWT efficiency already includes loses due to turbulent air and wind variability of strength and direction. What is your plan for control of the horizontal mill? How much faster and stronger must the control be? How much efficiency will you lose due to wind variation?

Want to know how to address lower efficiency of the VAWT? Make it bigger. Looks like VAWT is ahead.

 

humming along is this idea

Most forms of solutions from VAWT and HAWT suffer many complexity problems .
The first problem is the idea to put generator on the top of mast when for practical reasons the logic points to using hydraulic fluid to drive the underwater propeller as the way to go so looks like forget expensive batteries generators and electric motors .

The best rig cheapest and proven was the dutch sail windmills worked for many centuries pumping water .Efficiency isn't high as modern glass plastic props but the sails could be reefed and in some cases i think even as the wind mill was turning

The best candidate I can see is variation of the dutch Tjasker wind mill and instead to pump water , instead pump Hydraulic fluid to the underwater propeller https://en.wikipedia.org/wiki/Tjasker

Although Cats are not my favorite hull as they present too much underwater drag compared to mono hulls it would be easier to put a circular track to swing the Tjasker wind mill to face into the wind direction . Alternatively a Proa with suitable rudders at both ends and semi circle track might be the way to go . Direct down wind sailing accept its blowing a stink would probably be dismal but across the wind and into the wind sailing might not be so bad.

As the average wind strength in the world is about force three mono hulls will most days out preform cats and trimarans as they have less wetted surface area and less drag . Then it is possibly better to look a wide type mono hull with a oval track system for the Tjasker wind mill to get around the cat boat high drag solution

As the wind mill will probably be on the leeward side it might require lots of water ballasting for side on sailing to stop too much excessive leaning both downwards and upwards or steady small sail such as missen sail so as to remove the need to carry a keel or only to have water ballast keels for very windy days


It might also be possible to replace the older wooden lattice sail system with something like four wind surfer sailer masts with sails and some such solution with modifications


On the debate on the large diesel ships using lots of fuel here are some numbers to consider

A modern large container ship will do speeds of ~25knots and will for every ton of cargo moved use probably ~3 grams of fuel for each kilometer that one ton of cargo is moved
Compare that to an aircraft doing ~500 Knots it will need to use 600 grams of fuel per kilometer ton of cargo .
The ship will move with one liter of fuel a ton of cargo ~333 kilometers
the aircraft will move with one liter of fuel a ton of cargo ~1.4 kilometers

The modern ship on the tables of fuel use beats every thing trains, ships, trucks, you name it for grams of fuel used per ton per kilometer and is some ~200 times better for fuel per kilometer ton cargo than a aircraft .However the ship will take few weeks to go from Hong Kong to Europe where the plane will take a day so your fresh out of season strawberries will probably have to fly to get to you

The modern cargo ships often burn a horrible stuff basically looks like tar and it has to melted to make it flow into the engines.It has very high sulfur content and accounts for a big chunk of sulfur emissions in the world and the decks of these ships are often eaten away from the sulfur and chemicals that fall down from the funnel . Sulfur scrubbers like what exist on electric power stations that also burn this type of fuel would solve that problem but dont expect ships to fit those any time soon.

The modern ships engines some like the super tankers have ~25,000 BHP and sometimes burn the crude oil as fuel will return efficiency of ~50% due to their sheer massive sizes .Some of these engines are used in electric production stations due to their good efficiency . Car engines for example rarely exceed 30% efficiency with their fuel and most are less than 25% efficient with their fuel use shaft power and often are ~5% global efficient when all factors are added in .

Its not going to be easy with modern capital cost equipment to replace the very frugal cost per ton per kilometer of the modern cargo ships with wind power any time soon .The same money used to make sails on ships invested in improving the ships engine or hull drag with better paints will probably return more saving than the wind power sail solutions It is the problem the wind isn't very reliable or a strong form of power as most wind is about force 3 .Wind is interesting for fun sailors but has been dropped like a lead balloon when steam and later oil power arrived .


However a wind mill type solution might tickle a few for experimenting but if it is gonna work i suspect keep it cheap simple and not too big and try to use off the shelf parts and most important fairly light to test it for the first prototypes . Consider to make at first few small model boat versions to test out systems issues

 

I think there are too much loss in efficiency using hydraulics, even though it is extensively used for propulsion in heavy equipment they have plenty of available power, very few boats use hydraulic propulsion even though they have diesel power.

Steve.

 

I Know one large boat with Hydralic driven props

I once met a chap with home built 40 foot sailing cat with inboard and hydraulic drive system to two props .Yes he said there were losses but not as much as many think and it was lot cheaper and easier to install the engine a converted diesel car engine and he could control the cat better in the marina environments with twin screws and fine control of them . He figured 20% losses but as he was more the sailor type and only used engine for port entry he didn't think it was so great an issue .
If the power driving the hydraulics is wind power which isn't so expensive as diesel oil then some losses might be acceptable especially compared to complex electric generator battery solutions .Batteries are probably the most expensive power sources ever made with many lead acid batteries giving only best case ~500 cycles if driven hard and deep cycled and they can only store ~1% the energy per kilogram than diesel fuel can .The losses from a wind power generator to put power into batteries is often ~50% to convert the chemicals to useful,power and there are losses to take power out of batteries as well to factor in . The losses from a generator directly driving a electric engine below are about ~20% if you take the battery out of the equation and its cheaper .However your going to have kilowatts of power from the generator going down cables to electric engines where salt water can create expensive short circuits and possible fire risks and extra costs . Then there is often the generator power unit housed in the mast at high heights or complex cahin drives to the generator on the decks or hydraulic system with losses converting hydraulic to electric power and extra costs to do so
After that then when you fire up the marine diesel engine you either got to strap it onto direct driven separate propeller or have gear box that that can switch from electric motor to marine diesel motor or attach electric generator to drive the electric motor .
If you do the direct separate solution for marine diesel it is less losses in the system but probably more expensive more props etc

If you do the electric generator solution there will be cost of generator and interesting losses involved


If you have already got hydraulic driven prop system you only need another Hydraulic connector for the marine engine to connect to to drive the prop/s more simple but there will be losses 10% to 30% seems to be where it is at

However you should consult a hydraulic expert as they have their own issues and costs . The advantage is the drive system at the top of wind mast would probably be lighter and easier to install than electric power and probably less effected by pulsing issues that can come from the fact that the blade at lower sea levels can be impacted with lesser winds and other blanketing power pulse issues that be devil rotating wing and prop driven solutions

The Tjasker wind mill type system would keep the shaft drive to a electric generator or hydraulic system or direct geared on the deck of the craft


just my 2 cents worth on that